This invention relates to various improvements to gas-fired torch assemblies for welding and brazing, and also applies to gas flow control means of general utility.
With regard to gas flow control means in general, a wide variety of pressure regulators are commercially available. Many of these have a sensing chamber located in the flow path of the fluid being regulated, one wall of the chamber being formed by a peripherally supported diaphragm. A pressure spring applies mechanical force to the opposite face of the diaphragm to oppose the fluid pressure in the sensing chamber. The midportion of the diaphragm carries an actuator tube which opens and closes a control valve positioned between the source of pressurized fluid and the sensing chamber whereby the extent of valve opening is governed by the force differential across the diaphragm.
Regulators of the type discussed in the preceding paragraph have been made adjustable by providing rotatable means for adjusting the compression of the pressure spring, but such an arrangement is not practical in some instances; for example, when the regulator is on a gas-fired hand torch for brazing or welding where it is often important that the operator have one hand free to hold and manipulate the work-pieces. According to this invention, such regulators may be adjusted by one-handed operation.
Slide members with inclined valve actuating cam surfaces are known according to Phlipot, U.S. Pat. No. 3,511,266; however such prior devices have not been applied to the preferred type of pressure regulator disclosed herein, nor to gas fired torch assemblies.
According to one feature of this invention, one-handed operation of a gas-fired torch assembly is made possible by providing a valve operating means which includes a manually slidable member which is linearly movable in a direction transverse to the direction of valve movement, the manually slidable member having a cam surface inclined with respect to its axis to engage a follower operatively connected to the flow control valve. The operative connection between the cam surface and the valve may be directly against a valve stem or, in a pressure regulator device, may be against the diaphragm-biasing pressure spring where its action is opposed in part by fluid pressure on one side of a diaphragm.
In prior gas fired torches for welding, brazing and the like, there have been regulator or valve bodies which receive a laterally projecting tip base to which a welding or brazing tip is attached. Such tip bases have been mounted for swivelling movement about an axis transverse to the body, enabling a worker to keep the propane bottle or other source of liquified petroleum gas (LPG) in a somewhat upright position to prevent the discharge of liquid into the torch tip to produce flare up. Such prior devices have been constructed to permit removal of the swivelling tip base from the valve/regulator body, but they have not provided means for ensuring that no gas may be discharged after the tip base is removed. According to one feature of the present invention, there is provided in the flow path to the swivel tip base a safety cutoff valve which has a projecting actuator pin and is spring biased to a closed position. The safety cutoff valve will remain closed whenever the swivel tip base is separated from the apparatus. However, when the swivel tip base is connected to the valve/regulator housing, it will contact the actuator pin of the cutoff valve, opening the cutoff valve to permit gas to flow to the tip base. There is also provided a spring clip retainer for holding the swivel tip base on the valve/regulator housing, the spring clip retainer connecting being known per se but being novel with respect to the field of gas-fired torches.
Another feature of the apparatus disclosed herein pertains to tip bases for gas-fired torches, specifically those tip bases which are detachably connected to a torch handle or to a valve/regulator housing. Such tip bases are provided with minute gas-releasing openings which may become clogged by small particles of contaminants such as dust, particularly if the tip base is removed from the other components of the system and is carried loosely in a toolbox. To avert this condition, the present invention involves a tip base provided with an orifice at one end, an interior passage leading through the tip base to the orifice, and a dust plug located within the passage to seal the passage from the entry of contaminating particles when the tip base is loose in a toolbox. The dust plug is movable axially of the passage between a passage-sealing position and a passage-opening position, the latter position being the closer position to the orifice. The dust plug is biased to its passage-closing position but, upon being subjected to the pressure of gas, the dust plug is movable toward the orifice to its passage-opening position which it assumes during normal use of the tip base with a burner tip attached thereto.
The inventive features discussed hereinabove may be used in a wide variety of structures, only exemplary ones being shown in the drawings and described in the following specification.